Reductant Heater

ABSTRACT

A reductant heating system may include a reductant tank, a reductant tank flange and a hollow tube residing within the reductant tank and passing through the reductant tank flange in two locations to carry coolant into and out of the reductant tank. The reductant heating system may further include a resistive wire wrapped around the hollow tube within the reductant tank and an electrical supply cord located outside of the reductant tank that supplies electrical power to the resistive wire. A temperature detector may be disposed within the reductant tank to detect a temperature within the reductant tank and govern electricity flow to the resistive wire. That is, the temperature detector may be wired in-line in the resistive wire and may be a thermal switch attached to the hollow tube. In another embodiment, the temperature detector may be a thermocouple that senses a temperature within the reductant tank.

FIELD

The present disclosure relates to an apparatus and a method of controlfor heating a reductant in an exhaust treatment system.

BACKGROUND

This section provides background information related to the presentdisclosure which is not necessarily prior art. Selective CatalyticReduction (SCR) is a widely accepted technology for treating emission ofnitrogen oxides (NOx) from lean engine exhaust. The most common,commercially available SCR deNOx system is urea-SCR which uses aqueousurea solution and employs a thermolysis/hydrolysis procedure to generateammonia (NH3) from urea for NOx reduction over the SCR catalyst. Themajor challenges for the liquid urea system are its relatively highhardware costs and complicated control requirements. Anotherdisadvantage is that the urea solution contains excess water (more thanneeded for hydrolysis), which necessitates a large storage tank. Stillyet, another disadvantage is that reductants, such as urea, may freezewithin the storage tank. If such a reductant is unable to thaw, areductant pump may not prime and there is potential for a reductantinjector on the exhaust pipe to fail.

What is needed then is a device and method for heating a reductant.

SUMMARY

This section provides a general summary of disclosure material, and isnot a comprehensive disclosure of full scope or of all disclosurefeatures. A reductant heating system may include a reductant tank, areductant tank flange and a hollow tube residing within the reductanttank that passes through the reductant tank flange in a first locationto carry coolant into the reductant tank. The hollow tube may passthrough the reductant tank flange at a second location to carry coolantfrom the reductant tank. The reductant heating system may furtherinclude a resistive wire wrapped around the hollow tube within thereductant tank and an electrical supply cord located outside of thereductant tank that supplies electrical power to the resistive wire. Atemperature detector may be disposed within the reductant tank to detecta temperature within the reductant tank and govern electricity flow tothe resistive wire. The temperature detector may be wired in-line in theresistive wire and may be a thermal switch attached to the hollow tube.Alternatively, the temperature detector may be a thermocouple thatsenses a temperature within the reductant tank. Heating the resistivewire heats a reductant within the tank.

A 120 volt electrical source may supply electrical energy to a 120electrical supply cord that supplies power to the resistive wire. Acontroller may be disposed outside of the reductant tank and may bewired in-line with the electrical supply cord and receive communicationsfrom the thermocouple. An engine block heater may also be electricallywired to the 120 volt electrical source such that both, the engine blockheater and the resistive wire are powered by 120 volt household orcommercial power source. The engine block heater and the resistive wiremay be operated at the same time.

A method of controlling a reductant heating system may entail providinga hollow tube, such as for passage of an engine coolant, wrapped with aresistive wire into a reductant tank, providing an electrical supplycord located outside the reductant tank that supplies electricity to theresistive wire located inside the reductant tank, providing atemperature detector in-line in the resistive wire, and connecting theelectrical supply cord to a 120 volt electrical source.

The method of controlling a reductant heating system may further entaildetecting a temperature with the temperature detector and closingelectrical contacts within the temperature detector permittingelectricity to flow through the resistive wire, thus heating theresistive wire and interior volume of the reductant tank, including areductant. The method may further entail detecting a temperature withthe temperature detector and opening electrical contacts within thetemperature detector thereby causing electricity to stop flowing throughthe resistive wire thereby preventing any supply of heat.

The temperature detector may be a thermocouple and the method mayfurther entail providing a controller in-line with the electrical supplycord, and providing a communication wire between the thermocouple andthe controller. The method may then involve detecting a temperature withthe thermocouple and providing a signal from the thermocouple to thecontroller and permitting electricity to flow through the resistivewire. Alternatively, providing a signal from the thermocouple to thecontroller may cause the controller to control in such a way therebypreventing electricity from flowing through the resistive wire.

Further areas of applicability will become apparent from the descriptionprovided herein. The description and specific examples in this summaryare intended for purposes of illustration only and are not intended tolimit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only ofselected embodiments and not all possible implementations, and are notintended to limit the scope of the present disclosure.

FIG. 1 is a schematic view of a control system for reducing nitrogenoxides in an engine exhaust on a vehicle in accordance with the presentdisclosure;

FIG. 2 is an enlarged side view depicting a reductant heater andassociated controls in accordance with the present disclosure;

FIG. 3 is an enlarged perspective view depicting a reductant heater inaccordance with the present disclosure;

FIG. 4 is an enlarged view of a reductant tube wrapped by an electricheating element in accordance with the present disclosure;

FIG. 5 is a flowchart depicting a method of control for heating areductant of an emission control system; and

FIG. 6 is a flowchart depicting a method of control for heating areductant of an emission control system.

Corresponding reference numerals indicate corresponding parts throughoutthe several views of the drawings.

DETAILED DESCRIPTION

Example embodiments will now be described more fully with reference toFIGS. 1-6 of the accompanying drawings. FIG. 1 depicts an emissionscontrol system 10 situated within and utilized by an exemplary vehicle12, such as an automobile or a truck. Regardless of a particular weightclass within which vehicle 12 may be categorized, vehicle 12 may beequipped with an engine 14, which may be appropriately sized. Engine 14may be a gasoline fueled spark ignition engine or may be a diesel fueledcompression engine. Fuels for a gasoline engine may include gasoline,E85, E95 or other similar fuels. Fuels for a diesel engine may includediesel fuel, bio fuel B5, B10, B20 or other similar fuels. Engine 14 mayhave an exhaust port 16 that discharges combusted exhaust gases into anexhaust conduit 18, also known as an exhaust pipe. An exhaust stream 20of engine 14 flows from exhaust port 16 of engine 14 and through exhaustconduit 18 to an injector 22. Injector 22 may be a reductant injectorthat is positioned upon or through a wall of exhaust conduit 18 toinject a reductant into exhaust stream 20 flowing through exhaustconduit 18. An emissions catalyst 24 having an emissions catalyst inlet26 and an emissions catalyst outlet 28 may be positioned downstream ofinjector 22 and is in receipt of exhaust stream 20 such that exhauststream 20 is required to flow through emissions catalyst 24.

A fuel tank 30 may be mounted to vehicle 12 to store fuel, such asdiesel fuel, for engine 14. Fuel tank 30 may supply fuel to engine 14via a fuel supply line 32 such that fuel may be selectively supplied tocombustion chambers of engine 14. A reductant tank 34 also may bemounted to vehicle 12 and may store a reductant such as urea, or thelike. In one example, and with reference including FIG. 2, a user mayfill reductant tank 34 by conventional methods such as by dispensingreductant through a dedicated reductant tank filler neck 38 that permitsaccess to fill reductant tank 34. Reductant tank filler neck 38 may beequipped with a removable filler neck cap 40. A reductant level sensor42 may be provided in reductant tank 34 to communicate a reductantvolume signal through a signal line 44 to a controller 66, or othercontroller associated with injector 22. A reductant supply line 36 maybe configured to fluidly communicate the reductant from reductant tank34 to injector 22 as long as reductant level sensor 42 senses reductant45. An optional recirculation line 48 may be used to allow highinjection pressures and/or maintain reductant flow through injector 22for injector cooling purposes.

As depicted in FIGS. 1 and 2, a reductant heating system 50 may be partof emission control system 10. Reductant heating system 50 may includereductant tank 34, a coolant in tube 52, a coolant out tube 54, acoolant u-tube 56, and a reductant tank flange 58. Coolant in tube 52and coolant out tube 54 may both pass through reductant tank flange 58,which may be easily removable from a top surface 60 of reductant tank34, or other surface of reductant tank 34, such as a bottom surface 59.A threaded engagement may make the reductant tank flange 58 easilyremovable from reductant tank 34. Coolant in tube 52, coolant out tube54, and coolant u-tube 56 may be formed as a monolithic one-piece hollowtube 82.

Other components of reductant heating system 50 may include a resistiveheating wire 62, which may be wrapped around tubing within reductanttank 34. When resistive heating wire 62 is energized with electricity,heat produced by electrical resistance transfers to tubing of u-tube 56and surrounding frozen or liquid reductant, as will be further explainedlater. Resistive heating wire 62 may be circular in cross-section or maybe relatively flat or oval in cross-section. Other cross-sectionalshapes of resistive heating wire 62 are conceivable. While resistiveheating wire 62 may be located inside a volume of reductant tank 34, a120 volt electrical supply cord 64 may be located outside of a volume ofreductant tank 34 and carry or supply electricity to resistive heatingwire 62. Controller 66 may be located in an in-line fashion within 120volt electrical supply cord 64, which may be divided into two electricalbranches as depicted in FIG. 2.

One-hundred twenty (120) volt electrical supply cord 64 may derive itselectrical energy through a 120 volt electrical plug 70, which may bethe same or similar to those used in residential or commercialbusinesses in the United States or equivalent outside of the USA. 120volt electrical supply cord 64 may also supply or provide electricalenergy to electrical cord 72 which supplies electrical energy to a blockheater 74, which may reside in an engine block of engine 14.

FIGS. 3 and 4 depict enlarged perspective views of portions of reductantheating system 50. FIG. 3 depicts coolant in tube 52, coolant out tube54, and coolant u-tube 56. FIG. 3 also depicts a reductant level sendingunit 84, which may be an alternative to level sensor 42. Reductant levelsending unit 84 may be a manual float type of system which may detect alevel of reductant within reductant tank 34. A base 86 of reductantlevel sending unit 84 may contact a bottom inside surface 87 ofreductant tank 34 when flange 58 resides on tank top surface 60. FIG. 2depicts base 86 removed from u-tube 56 for clarity. FIG. 4 depictsresistive wire 62 wrapped around a straight portion of tube 82 such thatan outside surface of resistive wire 62 contacts an outside surface oftube 82. More specifically, resistive wire 62 may be encased in aninsulator, which may contact an outside surface of tube 82. Althoughu-tube 56 is depicted in various figures in conjunction with a coolantpassage through a volume of reductant tank 34, various configurations orshapes other than u-tube 56 are envisioned in connection with thepresent disclosure. Such configurations may be dictated by the shape ofreductant tank 34 or heat transfer characteristics of tube 82 and heattransfer characteristics of resistive wire 62.

FIG. 5 is a flowchart 100 depicting a method of control for heating areductant of an emission control system. Method steps of flowchart 100begin at start block 102 and proceed to block 104 where a 120 voltelectrical plug 70 of a block heater 74 may be plugged into a 120 voltsource, such as a wall receptacle 88 of a residential or commercialbuilding wall 91 that is supplied with 120 volt electrical power. Beforeplugging in 120 volt electrical plug 70, engine 14 may be turned off.When electrical plug 70 is plugged into a receptacle 88, electricalenergy may pass through 120 volt electrical supply cord 64. Uponconnecting electrical plug 70 of block heater 74 into a 120 volt source,the method proceeds to block 106 where an inquiry is made as to whethera temperature of reductant is less than a predetermined thresholdtemperature. If the response to the inquiry of inquiry block 106 isaffirmative, then the method proceeds to block 108 where a temperaturedetector such as a thermal switch 90 closes thereby causing electricalenergy to activate or energize the resistive wire 62 wrapped around tube82 within reductant tank 34. However, if the response to the inquiry ofinquiry block 106 is negative, then the method proceeds to block 110where thermal switch 90 opens or remains open thereby preventingelectrical energy from activating or energizing resistive wire 62wrapped around tube 82 within reductant tank 34.

To either cause electrical energy to activate or energize resistive wire62 wrapped around tube 82 or to not activate and prevent electricalenergy from energizing resistive wire 62 wrapped around tube 82, switch90 may be a thermally-activated in-line switch that opens or closesswitch contacts in accordance with a predetermined temperature to whichswitch 90 is subjected or exposed. Closing of contacts may permitelectrical energy to flow through resistive wire 62 thereby heatingreductant within reductant tank 34, while opening of contacts mayprevent electrical energy from flowing through resistive wire 62 therebypreventing any heating of reductant within reductant tank 34.

FIG. 6 is a flowchart 200 depicting a method of control for heating afrozen or liquid reductant of an emission control system. The method offlowchart 200 begins at start block 202 and proceeds to block 204 wherea 120 volt electrical plug 70 of a block heater 74 is plugged into a 120volt source, such as a wall receptacle 88 of a residential or commercialbuilding wall 91 that is supplied with 120 volt electrical power. Whenelectrical plug 70 is plugged into a receptacle 88, electrical energymay pass through 120 volt electrical supply cord 64. Upon connectingelectrical plug 70 of block heater 74 into a 120 volt source, the methodproceeds to block 206 where a thermocouple 92 reads or detects atemperature of frozen reductant or liquid (non-frozen) reductant withinreductant tank 34. Thermocouple 92 may communicate directly withreductant tank heat controller 66 via a communication wire 94 (FIGS. 1and 2).

Control within flowchart 200 proceeds to inquiry block 208 where aninquiry is made as to whether a temperature of reductant sensed bythermocouple 92 is less than a predetermined threshold temperature, suchas a threshold “ON” temperature. If the response to the inquiry ofinquiry block 208 is affirmative, then the method proceeds to block 210where controller 66 permits the flow of electricity to resistive wire 62wrapped around tube 82 within reductant tank 34. Flow of electricitycauses heating of resistive wire 62 and tube 82 to heat reductant withinreductant tank 34. However, if the response to the inquiry of inquiryblock 208 is negative, then the method proceeds to block 212 wherecontroller 66 prevents the flow of electricity to resistive wire 62wrapped around tube 82 within reductant tank 34. With no flow ofelectricity to resistive wire 62, resistive wire 62 and tubing 82 do notheat within reductant tank 34, thereby preventing any heating ofreductant within reductant tank 34 by resistive wire 62. Thus, reductanttank heat controller 66 may act as a gateway for electricity supplied toresistive wire 62 wrapped around tube 82, which may be formed intocoolant u-tube 56, for example. Thus, controller 66 and thermocouple 92communicate via communication wire 94.

Reductant heating system 50 may employ reductant tank 34, hollow tube 82passing into and from reductant tank 34 that carries a flowing coolant,such as an engine coolant, resistive wire 62 wrapped around hollow tube82, and temperature detector 90 disposed within reductant tank 34 todetect a temperature within reductant tank 34 and govern electricityflow to resistive wire 62. Reductant tank flange 58 may be arranged overa hole or aperture in reductant tank 34 such that hollow tube 82residing within the reductant tank may pass through reductant tankflange 58 in a first location to carry coolant into reductant tank 34and through reductant tank flange 58 at a second location to carrycoolant from reductant tank 58. Coolant flowing through tube 82 may bean engine coolant that warms reductant within reductant tank 34 whenengine 14 is running and engine 14 heats engine coolant. Coolant flowingthrough reductant tank flange 58 in a first location and throughreductant tank flange 58 at a second location may be part of an enginecoolant loop, which includes coolant circulating through a water jacketaround engine block of engine 14.

Temperature detector 90 may be a thermal switch disposed in-line inresistive wire 62 to control electricity flow in accordance with asensed temperature. Resistive wire 62 may be electrically connected to a120 volt electrical source, such as at a household or commercialbuilding. In some instances, resistive wire 62 only may be electricallyconnected to a 120 volt electrical source (i.e. household or commercialbuilding current), and not vehicle-supplied or vehicle-generatedcurrent. The temperature detector may be thermocouple 92 and controller66 may be wired in-line with 120 volt electrical source thatcommunicates with the thermocouple. Controller 66 may be disposedoutside of reductant tank 34. The temperature detector may be wiredin-line in resistive wire 62. The temperature detector, regardless ofwhether it is a thermal switch or a thermocouple, may be attached tohollow tube 82.

Engine block heater 74 may be electrically wired to 120 volt electricalsource receptacle 88, which may supply electrical power to engine blockheater 74 and resistive wire 62 at the same time through electricalsupply cord 64. That is, engine block heater 74 and resistive wire 62may not be powered by vehicle-generated electricity (e.g. a generator)and may not be powered by an on-board battery.

A method of controlling a reductant heating system 50 may entailproviding hollow tube 82 wrapped with resistive wire 62 into reductanttank 34, providing electrical supply cord 64 located outside reductanttank 34 to supply electricity to resistive wire 62 located insidereductant tank 34, providing a temperature detector 90, 92, which may bein-line in resistive wire 62, and connecting electrical supply cord 64to a 120 volt electrical source.

The method may further entail detecting a temperature with temperaturedetector 92 and closing electrical contacts within temperature detector92 thereby permitting electricity to flow through resistive wire 62, ordetecting a temperature with temperature detector 92 and openingelectrical contacts within temperature detector 92 thereby preventingelectricity from flowing through resistive wire 62. Temperature detector92 may, for example, work on the principles of a bi-metallic strip suchthat one or more metal tabs move (e.g. closing or opening contact) as aresult of temperature changes.

The temperature detector may be thermocouple 92 and the method mayfurther entail providing controller 66 in-line with electrical supplycord 64, providing communication wire 94 between thermocouple 92 andcontroller 66, detecting a temperature with thermocouple 92, andproviding a signal from thermocouple 92 to controller 66 and permittingelectricity to flow through resistive wire 62 or providing a signal fromthermocouple 92 to controller 66 and preventing electricity from flowingthrough resistive wire 62.

While the present disclosure may utilize 120 volt power supplied by a120 volt household or commercial power source, an auxiliary power unit214 (“APU”) may be utilized as an alternative to a 120 volt household orcommercial power source. The auxiliary power unit 214 (“APU”) may be anon-board power unit. That is, an on-board power unit may be a powerunit, such as an internal combustion engine coupled with an electricalgenerator that is completely contained upon a vehicle, with no wires orother connections to a residential or commercial building. Morespecifically, as depicted in FIG. 1, an auxiliary power unit 214 may beemployed to supply electrical power through an auxiliary power unit cord216, which may derive its electrical energy. Auxiliary power unit cord216 may also supply or provide electrical energy to electrical cord 72which supplies electrical energy to a block heater 74, which may residein an engine block of engine 14, as described above.

Auxiliary power unit 214 may be a gasoline or diesel engine and mayemploy a generator that is capable of providing a range of power. Forexample, auxiliary power unit 214 may supply 6500 Watts of power topower block heater 74 and reductant heating system 50. However,auxiliary power unit 214 may be sized to supply any level of power (e.g.watts) or a range of power, depending upon the electrical draw or loadof block heater 74 and reductant heating system 50. Auxiliary power unit214 may be equipped with electric start, remote start, remote glow plugif powered by a diesel engine, and may be equipped with 20 A breakers,for example, although precise configuration may be determined by theloads (e.g. block heater 74 and reductant heating system 50) to besupplied. An advantage of utilizing APU 214 is that vehicle 12 may beable to power block heater 74 and reductant heating system 50 even when120 volt household or commercial power source is not available. Thus,vehicle 12 may be completely self-sustaining with regard to poweringblock heater 74 and reductant heating system 50. In one configuration,APU 214 may utilize an 11 HP diesel engine, which when equipped with a6500 W generator, may generate 46 A at 120V, 23 A at 240V, and 8.3 A at12V. Other power output configurations are conceivable. When APU 214 isoperating and supplying electrical power to block heater 74 andreductant heating system 50, 120 volt electrical plug 70 will not beplugged into a 120 volt household or commercial power source.

There are multiple advantages of the present disclosure. One aspect isthat the electrical heating wrap may be plugged into land-basedelectrical supply voltage (e.g. residential or commercially available120 v voltage source) to permit heating of frozen, semi-frozen, orliquid reductant within reductant tank 34 at the same time that anengine block heater is operating from the same 120 volt electricalsupply to warm an engine 14, such as a diesel engine used within adiesel road tractor, on-road equipment or off-road equipment. Anotheraspect is that instead of utilizing a land-based electrical supplyvoltage (e.g. residential or commercially available 120 v voltagesource), APU 214 may utilize an on-board diesel or gasoline engineequipped with a power generator, which may generate the requisiteamperes and voltage to power block heater 74 and reductant heatingsystem 50. In such a manner, reductant within a reductant tank may thawand will not be frozen and thus be waiting and ready to be used for NOxreduction upon starting of an engine employing reductant tank 34. Thus,waiting for frozen reductant to thaw will not be necessary which greatlyreduces the time necessary for an emission control system 10 to beginemitting environmentally friendly exhaust from an exhaust tail pipeoutlet.

Methods depicted in FIGS. 5 and 6 may be applied to a vehicle whoseengine is not running or operating. Thus, engine 14 may be turned off asa process step of the processes described above in conjunction withFIGS. 5 and 6. When engine 14 starts, controller 66 may or may not beconfigured to stop electricity from flowing through resistive wire 62.

The foregoing description of the embodiments has been provided forpurposes of illustration and description. It is not intended to beexhaustive or to limit the disclosure. Individual elements or featuresof a particular embodiment are generally not limited to that particularembodiment, but, where applicable, are interchangeable and can be usedin a selected embodiment, even if not specifically shown or described.The same may also be varied in many ways. Such variations are not to beregarded as a departure from the disclosure, and all such modificationsare intended to be included within the scope of the disclosure.

Example embodiments are provided so that this disclosure will bethorough, and will fully convey the scope to those who are skilled inthe art. Numerous specific details are set forth such as examples ofspecific components, devices, and methods, to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to those skilled in the art that specific details need not beemployed, that example embodiments may be embodied in many differentforms and that neither should be construed to limit the scope of thedisclosure. In some example embodiments, well-known processes,well-known device structures, and well-known technologies are notdescribed in detail. The method steps, processes, and operationsdescribed herein are not to be construed as necessarily requiring theirperformance in the particular order discussed or illustrated, unlessspecifically identified as an order of performance. It is also to beunderstood that additional or alternative steps may be employed.

When an element or layer is referred to as being “on,” “engaged to,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto,” “directly connected to,” or “directly coupled to” another elementor layer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,”“lower,” “above,” “upper,” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. Spatiallyrelative terms may be intended to encompass different orientations ofthe device in use or operation in addition to the orientation depictedin the figures. For example, if the device in the figures is turnedover, elements described as “below” or “beneath” other elements orfeatures would then be oriented “above” the other elements or features.Thus, the example term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein interpreted accordingly.

1. A reductant heating system comprising: a reductant tank; a hollowtube passing into and from the reductant tank, the hollow tubecontaining a coolant; a resistive wire wrapped around the hollow tube;and a temperature detector disposed within the reductant tank to detecta temperature within the reductant tank and govern electricity flow tothe resistive wire.
 2. The reductant heating system according to claim1, wherein the temperature detector is a thermal switch.
 3. Thereductant heating system according to claim 2, wherein the thermalswitch is disposed in-line in the resistive wire to control electricityflow in accordance with a sensed temperature.
 4. The reductant heatingsystem according to claim 3, wherein the resistive wire is electricallyconnected to a 120 volt electrical source.
 5. The reductant heatingsystem according to claim 1, wherein the temperature detector is athermocouple and the reductant heating system further comprises: a 120volt electrical source; and a controller wired in-line with the 120 voltelectrical source that communicates with the thermocouple.
 6. Thereductant heating system according to claim 5, further comprising: anengine block heater electrically wired to the 120 volt electricalsource, wherein the 120 volt electrical source supplies electrical powerto the engine block heater and the resistive wire at the same time. 7.The reductant heating system according to claim 5, further comprising:an auxiliary power unit, wherein the auxiliary power unit is the 120volt electrical source.
 8. The reductant heating system according toclaim 7, further comprising: a vehicle, wherein the auxiliary power unitis completely contained upon the vehicle.
 9. A reductant heating systemcomprising: a reductant tank; a reductant tank flange; a hollow tuberesiding within the reductant tank and passing through the reductanttank flange in a first location to carry coolant into the reductant tankand through the reductant tank flange at a second location to carrycoolant from the reductant tank; a resistive wire wrapped around thehollow tube within the reductant tank; an electrical supply cord locatedoutside of the reductant tank that supplies electrical power to theresistive wire; and a temperature detector disposed within the reductanttank to detect a temperature within the reductant tank and governelectricity flow to the resistive wire.
 10. The reductant heating systemaccording to claim 9, wherein the temperature detector is wired in-linein the resistive wire.
 11. The reductant heating system according toclaim 10, wherein the temperature detector is a thermal switch attachedto the hollow tube.
 12. The reductant heating system according to claim10, wherein the temperature detector is a thermocouple that senses atemperature within the reductant tank.
 13. The reductant heating systemaccording to claim 12, further comprising: a 120 volt electrical source,the electrical supply cord electrically connected to the 120 voltelectrical source; and a controller wired in-line with the electricalsupply cord, the controller in communication with the thermocouple. 14.The reductant heating system according to claim 13, further comprising:an engine block heater, wherein the engine block heater is electricallywired to the 120 volt electrical source.
 15. The reductant heatingsystem according to claim 14, wherein the controller is disposed outsideof the reductant tank.
 16. The reductant heating system according toclaim 15, further comprising: a reductant level sensor connected to thehollow tube residing within the reductant tank.
 17. The reductantheating system according to claim 13, further comprising: an auxiliarypower unit, wherein the auxiliary power unit is the 120 volt electricalsource.
 18. The reductant heating system according to claim 17, furthercomprising: a vehicle, wherein the auxiliary power unit is completelycontained upon the vehicle.
 19. A method of controlling a reductantheating system, the method comprising: providing a hollow tube wrappedwith a resistive wire into a reductant tank; providing an electricalsupply cord located outside the reductant tank that supplies electricityto the resistive wire located inside the reductant tank; providing atemperature detector in-line in the resistive wire; connecting theelectrical supply cord to a 120 volt electrical source; detecting atemperature with the temperature detector; and selectively supplyingelectricity from the source to the resistive wire based on the detectedtemperature.
 20. The method of controlling a reductant heating systemaccording to claim 19, the method further comprising: closing electricalcontacts within the temperature detector permitting electricity to flowthrough the resistive wire.
 21. The method of controlling a reductantheating system according to claim 19, the method further comprising:opening electrical contacts within the temperature detector causingelectricity to stop flowing through the resistive wire.
 22. The methodof controlling a reductant heating system according to claim 19, whereinthe temperature detector is a thermocouple, the method furthercomprising: providing a controller in-line with the electrical supplycord; and providing a communication wire between the thermocouple andthe controller.
 23. The method of controlling a reductant heating systemaccording to claim 22, the method further comprising: detecting atemperature with the thermocouple; and providing a signal from thethermocouple to the controller and permitting electricity to flowthrough the resistive wire.
 24. The method of controlling a reductantheating system according to claim 22, the method further comprising:detecting a temperature with the thermocouple; and providing a signalfrom the thermocouple to the controller and preventing electricity fromflowing through the resistive wire.
 25. The method of controlling areductant heating system according to claim 19, further comprising:providing an auxiliary power unit, wherein the auxiliary power unit isthe 120 volt electrical source.
 26. The reductant heating systemaccording to claim 25, further comprising: providing a vehicle, whereinthe auxiliary power unit is completely contained upon the vehicle.